#include "config.h"

#define DBG_SUBSYS      S_LIBINTERFACE

#include "iscsi.h"
#include "dbg.h"

/*
 * This is the CRC-32C table
 * Generated with:
 * width = 32 bits
 * poly = 0x1EDC6F41
 * reflect input bytes = true
 * reflect output bytes = true
 */

u32 iscsi_crc32c_table[256] = {
    0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
    0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
    0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
    0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
    0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
    0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
    0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
    0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
    0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
    0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
    0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
    0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
    0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
    0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
    0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
    0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
    0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
    0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
    0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
    0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
    0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
    0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
    0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
    0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
    0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
    0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
    0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
    0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
    0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
    0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
    0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
    0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
    0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
    0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
    0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
    0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
    0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
    0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
    0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
    0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
    0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
    0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
    0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
    0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
    0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
    0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
    0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
    0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
    0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
    0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
    0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
    0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
    0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
    0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
    0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
    0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
    0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
    0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
    0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
    0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
    0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
    0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
    0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
    0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
};

/*
 * Steps through buffer one byte at at time, calculates reflected crc using table.
 */

static u32 iscsi_crc32c(void *address, unsigned long length)
{
    u8 *buffer = address;
    u32 crc = 0xffffffff, result;

    while (length--)
	crc = iscsi_crc32c_table[(crc ^ *buffer++) & 0xFFL] ^ (crc >> 8);
    result = crc ^ 0xffffffff;

    return result;
}

/*
 * Continues stepping through buffer one byte at at time,
 * calculates reflected crc using table.
 */
u32 iscsi_crc32c_continued(void *address, unsigned long length, u32 crc)
{
    u8 *buffer = address;
    u32 result;

    crc = crc ^ 0xffffffff;
    while (length--)
	crc = iscsi_crc32c_table[(crc ^ *buffer++) & 0xFFL] ^ (crc >> 8);
    result = crc ^ 0xffffffff;

    return result;
}

static void digest_header(struct iscsi_pdu *pdu, u8 *_crc)
{
        u32 crc;

        crc = iscsi_crc32c(&pdu->bhs, sizeof(pdu->bhs));
        if (pdu->ahssize)
                crc = iscsi_crc32c_continued(pdu->ahs, pdu->ahssize, crc);

        memcpy(_crc, &crc, sizeof(u32));
}

int digest_rx_header(struct iscsi_cmd *cmd)
{
        int ret = 0;
        u32 crc;

        digest_header(&cmd->pdu, (u8 *)&crc);

        if (crc != cmd->hdigest)
                ret = EIO;

        return ret;
}

int digest_tx_header(struct iscsi_cmd *cmd)
{
        cmd->hdigest = iscsi_crc32c(&cmd->pdu.bhs, sizeof(cmd->pdu.bhs));
        return 0;
}

static void digest_data(struct iscsi_cmd *cmd, struct iscsi_tio *tio, u32 offset, u8 *_crc)
{
        int i, count;
        u32 crc, size;
        char buf[MAX_BUF_LEN];
        struct iovec *iov;

        (void) cmd;
        iov = (void *)buf;
        size = iscsi_cmd_size_align(cmd->pdu.datasize);
        mbuffer_trans2(iov, &count, offset, size, &tio->buffer);

        crc = 0;
        for (i = 0; i < count; ++i) {
                crc = iscsi_crc32c_continued(iov[i].iov_base, iov[i].iov_len, crc);
        }

        memcpy(_crc, &crc, sizeof(u32));
}

int digest_rx_data(struct iscsi_cmd *cmd)
{
        int ret;
        struct iscsi_tio *tio;
        struct iscsi_cmd *scsi_cmd;
        struct iscsi_data_out_hdr *req;
        u32 offset, crc;

        switch (cmd_opcode(cmd)) {
        case ISCSI_OP_SCSI_REJECT:
        case ISCSI_OP_PDU_REJECT:
        case ISCSI_OP_DATA_REJECT:
                goto out;
        case ISCSI_OP_SCSI_DATA_OUT:
                scsi_cmd = cmd->req;
                req = (struct iscsi_data_out_hdr *)&cmd->pdu.bhs;
                tio = scsi_cmd->tio;
                offset = be32_to_cpu(req->buffer_offset);
                break;
        default:
                tio = cmd->tio;
                offset = 0;
        }

        digest_data(cmd, tio, offset, (u8 *)&crc);
        if (crc != cmd->ddigest) {
                ret = EIO;
                GOTO(err_ret, ret);
        }
out:
        return 0;
err_ret:
        return ret;
}

int digest_tx_data(struct iscsi_cmd *cmd)
{
        digest_data(cmd, cmd->tio, 0, (u8 *)&cmd->ddigest);
        return 0;
}
